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As promised almost a month ago (previous thread) I'm posting up some info on my custom stealth cutout controller. Actually a month isn't too bad of turnaround time going from idea to (mostly) finished product. The basic idea was that the switch provided with my QTP 3" cutout is big, clunky, and is hard to hide. Could have probably made one of those ash-tray switch plates, but that's too easy . Instead, since I had a three-switch panel with a fog-light switch in a car without fog-lights, I decided to repurpose that slot for a stealthy cutout install. I'm using a defrost switch with the foglight faceplate for the momentary press both directions. Holding the button jogs the motor for as long as you hold it, and if you double tap the button quickly it will jog all the way closed or all the way open. I integrated a current sensing circuit to stop the motor whenever it gets to full lock either direction, as well as a timeout in case the current sensing ever fails for some reason. I also control the LED in the switch as a status indicator. Overall I'm pretty happy with how it turned out although I would change some things like size of the holes for the wires if I were to get another board made. I certainly don't claim to be an electrical engineer, but hey at least it works. Here's some pics (sorry if the images are a bit large):
The prototype made up on a breadboard:
Top board (not my best routing/layout job, admittedly):
Bottom board:
Assembled board before wrapping in 1" heat shrink:
I can post some more information like schematics and code if anyone is interested. Might make a video before I install it too. If for some reason someone else plans on building one of these I'll probably go back and fix the minor issues I found when building mine.
Just got it installed and it's pretty fun. The Magnaflow exhaust is certainly "quieter" than my full 2.25" exhaust, so it's nice to be able to really open it up every so often. Or open it half-way-ish to get about to the same volume as it had before. The Magnaflow exhaust is very deep, especially at idle.
Kewl. Would also be simple to make it open at a desired throttle %
Yeah, wouldn't be too hard. Would potentially have to account for difference in voltage (since it changes the speed of the motor) but I'm happy with it being semi-manual .
I would be interested in this controller for my power windows.
Nice work.
Probably wouldn't quite cut it for those motors, this one is only designed for 0.5 amp max. I do recall there are some auto-up/auto-down harnesses being sold with the relay kit.
Considering you tagged this in another thread and I somehow missed this last spring when you posted it, I would definitely be interested in learning more about how this worked out. I have to tear out the centre section of my exhaust for another fab project shortly and will be dropping in a QTP cutout while I'm there. Still got your project notes nearby?
I've attached the source code. I had to rename it to '.txt', it was originally '.c'. As long as you know how to read C it should be fairly self explanatory I think. A couple of noteworthy items:
Since the button has three states, we need to use two pins to determine if the button is connected to GND, +5V, or floating. To check the state, we set the first pin to +5V. If the second pin reads GND then we know it's being pressed in one direction. Then we set the output pin to GND. If the input pin reads +5V we know the button is pressed the other direction. If the input pin followed the output pin in both cases then the button's not being pressed.
The code is run off a fixed interval triggered by the timer interrupt. There's a lot of logic which uses time delays, such as the logic to determine if the button has been held down long enough to not register as a double click.
Nice idea. And there is nothing wrong with your board design. I have seen a lot of "professional" boards that looked terrible.
Do you get any electrical noise interference with the 5v regulator?
I made a Knight Rider flashing light circuit over 30 years ago and had "noise" drive it crazy.
Does the QTP cutout seal completely closed?
No real noticable noise from the 5V regulator, especially since I used capacitors as per the datasheet suggestion. The QTP cutout seals completely closed apart from some leakage around where the shaft goes through the bushings. I've been meaning to address that, but I was going to make a blockoff plate and clear up any other leaks first to see if it's the culprit behind my exhaust "tick".
05-11-2016, 10:36 AM
. Instead, since I had a three-switch panel with a fog-light switch in a car without fog-lights, I decided to repurpose that slot for a stealthy cutout install. I'm using a defrost switch with the foglight faceplate for the momentary press both directions. Holding the button jogs the motor for as long as you hold it, and if you double tap the button quickly it will jog all the way closed or all the way open. I integrated a current sensing circuit to stop the motor whenever it gets to full lock either direction, as well as a timeout in case the current sensing ever fails for some reason. I also control the LED in the switch as a status indicator. Overall I'm pretty happy with how it turned out although I would change some things like size of the holes for the wires if I were to get another board made. I certainly don't claim to be an electrical engineer, but hey at least it works. Here's some pics (sorry if the images are a bit large):
